Lifting jack



ot. 1,1930. MENSEN 1,777,566.

LIFTING JACK Filed neg. 15, 192s /l l ,v v

, ne s `Patented Qct. 7, 1930 srArlSd GUNNARJENSEN, or encina;` wisconsin, Assistme. 'To WALKER` MANUFACTURING.

COMPANY, OF RACINE, TNISCONSINQA. CORPGRATION OF XVI'SCONSIN LIFTING JACK Applicationriled December 1.5, 1928. Serial No. 326,316.

l are successively elevated to obtain along lift in proportion to the height'otl the ack `when lowered. y n

The principal object of the invention is to provide improved means for yieldably resisting rotary movement of one of the screw members `while permitting same to travel freely in a vertical direction. This means consists of a wire spring which is anchored in the lower end ofthe screw member and is formed with outwardly bowed spring loops which engage the inner cylindrical walls of the bore in the stationary standard through which the screw member travels..

Other objects and advantages ,of this invention willbe more apparent from Vthe following detailed description of one approved form of mechanism embodying the principles of this invention. Inptheaccompanying drawings:

Fig. 1 is a longitudinal. vertlcalsection through the lifting jack, inpartially elevated position. y

Fig. 2 is a transverse horizontal section, on an enlarged scale, taken substantially on the line2-2 of Fig. 1 andlooking in the direcy tion of the arrows.

The stationary supporting standard, in the form here shown, consists of an integral castingforined with an upstandingcylindrical portionH 1 and a comparatively large iiat supporting base 2, there being strengthening webs 3 between the base and the vertically extending tubular portion of the standard. A cylindrical bore 4;, having comparatively smooth cylindrical side walls, extends vertically through the standard, this bore being closed at the bottomr in any suitable manner as by the closure plate 5. The upper end of the standard is'enlarged, as at 6, to form a `support for the driving gear or nut 7, as

hereinafter described. An inwardlv projecting flange 8 at the top ofthe standard, and an upper spaced bracket loop 9 Vextending from the head 6, are lformed with vertically aligned openings adapted to serve as guides for the threaded sleeve 10, `which serves as the outer lifting screw.

The hub,A 11 of the driving gear 7 is internally threaded so as to serve as a nut, through which the externalthreads 12 of the sleeve are threaded. An anti-friction bearing Vcomprising the upperand lower raceways 13 and 14.- and an annular series ofballs 15 confined in a cage 16, serves to support the driving vgear 7 and nut 11 from the head 6 of the standard. rlhe nut 11 is of slightly less vertical height than the distance between head 6 and the upper portion of bracket 9.

A beveled driving'pinion 17 is rotatably supported on a stud 18secured in an enlargement or boss 19 at one side of the upper end of standard 1. The outwardly extending hub 20 of pinion 17 4is formed with a non- 4circular socket 21 to receive the correspondingly shaped end 22 of the detachable jack handle. y y

Stud 18 is formed with a main cylindrical portion-on which the pinion 17 is journaled, and has an enlarged head or annular shoulder 23 seated in a correspondingly shaped recess in the bottom ofsocket 21, whereby the pintate. The. stud 18`has a-shoulder 24 ng .),'ag-

ing-the outerface of the enlargement 19 on.

standard 1,and a restricted end portion 25 secured ina socket 26 in the boss 19 brT means of a pinor rivet,27. A ,e

The upper end portion of sleeve 10 is internally threaded, as indicated at 28, and an inner liftingv screw 29 meshes within the threads 28. Aliftingk head 30 for ,engaging andsupporting the load is secured at theupper end of screw 29. A stop 31 which maybe formed by striking 4upwardly a portion Vof one of the threads, orV may alternatively be in the form of'. an interposed pin, is provided near the lower end of screw 29 to engage the lower end of the nut formed by threads 28so as to limit the upward movement of screw 29 out of 4sleeve 10. `A similar stop 32 is formed near the lower end of the externally threaded portion 12 of sleeve 10, this stop 32 engaging a sheared-oif thread in the lower end of nut 11 and serving as a means for r0- tating the sleeve 10. An external stop 33 near the upper end of sleeve 10 limits the lowering movement of this threaded sleeve and also serves as a means for rotating sleeve l0 by engaging a sheared-olf thread at the top of nut 1l.

Vhen a load is supported by the head 30, the inner screw 29 will be held against rotation. If the sleeve l() `is rotated, the non-.rotating screw 29 will be forced to move vertically through the nut 2,8 in the upper end of sleeve l0. When the handle 22 is rotated, the rotary mor ement will be imparted to the dri-ving nut ll through the intermeshing gears 7 and 17. If the threadedsleeve' l0 rotates.

with the nut ll, it will serve to cause the nut 28 to'rotate and thus screw up or down the non-rotary inner screw 29. If, on the other hand, the sleeve l() is held against rotation, it will be moved up or down through the rotating nut ll, thus carrying the inner loadesupporting screw 29 bodily with it.v As a net result ot these movements, a continuous rotary movement imparted to t-he handle 22, will cause the two screws 29 and-l0 to be moved to their extreme vertical limits in one direction or the other. This can only take place, however, with the structure thus far described, when a load is supported on head 30 so as to hold the inner screw against rotation. In the absence of such a load, the screwsy will merely turn bodily with the nut, l1 and not change their vertical positions., whatever these may be.

According to the present invention, means is provided to yieldably resist the rotary movement of sleeve 10, so that this sleeve will move vertically through driving nut 1l, even though no load is supported by the inner screw 29. In the example here shown, a pair of diametrically opposed radial holes 0r openings 34 are formed in the lower end portion of threaded sleeve 10. Positioned at v9.() degrees to the openings 28 are a pair of radial slots 35 open at their lower ends.

wire spring 36 consists of a Acentral straight portion 37 from each end of which is bent a spring loop 38 terminating in an inwardly extending end portion 39, thetwo ends 39 projecting toward one another. The straight central portion 37 of the spring is inserted in the slots 35 and the bottom edges of these slots are peened over the wire to hold it in place. The spring ends 39 are snapped into the holes 34. The outwardly bowed spring loops 38 will frictionally engage the inner cylindrical surface t of the bore of the standard, and will offer a greater resistance to rotary movement of the sleeve in the bore than it does to vert-ical movement of the sleeve through the bore. A s a result, when driving nut ll is rotated, the sleeve 10 will not rotate, but will be moved vertically through the nut until one of the upper or lower limit stops 33 or 32 engage the sheared threads on the upper or lower facesof nut ll, after which the sleeve will be forced to rotate with driving nut ll in spite of the frictional resistance oliered by the bowed spring loops 38.

In operation, the jack may be placed beneath the load with both screws lO and 29 completely lowered and nested within the standard. At this time the inner screw 2,9 will not be in engagement with the load and there will be nothing to prevent the rotation of this inner screw. However, when the driving nut l1 is rotated in the proper direction, the screw sleeve l0 will be elevated through the driving nut ll, since this sleeve is held against rotation by the rictional resistance or spring loops 38 against the inner surface of the bore in the standard. This movement will continue until the stop 32A has engaged the sheared thread on the under surface of nut ll, after which the sleeve 10 will be forced to rotate with the driving nut. However, before this position is reached, the head 30 on inner screw 29 will have engaged the load, so that when sleeve l0 rotates with the nut ll, the rotary nut 28 in the upper end of sleeve l0 will serve to elevatethe inner screw 29.

The screws are lowered by turning the han dle 22 in the reverse direction. and thus re versing the direction of rotation of driving nut ll and sleeve l0. The sleeve 10 will be held from rotation by the bowed springs 38 so that it will be lowered completely into the standard, that is until stop 33 engages the sheared off thread on the upper surface of nut ll, after which it will rotate with the nut ll to lower the inner screw 29 into the standard, so long as screw 27 is held against rotation by its engagement with the load, or in any other manner.

I claim:

l. In a lifting jack comprising a standard having a cylindrical bore, a lifting member movable longitudinally through the bore, and means supported bythe standard and having rotatable engagement with the lifting member 'for moving it longitudinally in the bore, means for yieldingly resistingrotary movement of the member in the bore comprising a wire spring, the inner end portion oi2 the member being formed with a plurality of circumferentially spaced substantially radial openings, the intermediate portion of the spring being engaged in certain of the openings, and each end portion being looped outwardly and circumferentially of the member with the free end inserted inwardly through another opening.

2. In a lifting jack comprising a standard having a cylindrical bore, a lifting member movable longitudinally through the bor'e, and means supported by the standard and having rotatable engagement with the lifting member for moving it longitudinally in the bore, means for yieldingly resisting roi Ul tary movement of the member in the bore comprising a wire spring,`the inner end portion of the member being,formed` with a plir rality of circumferentially spaced substantially radial openings, the spring being positioned in the openings so as to form an out-` wardly bowed circumferentially extending the bore, means for yieldingly resisting ro-y tary movement of the member in the bore comprising a wire spring, the inner end portion of the member being formed with a pluV rality of circumferentiallyspaced substan tially radial openings, the spring being positioned in the openings so as to form outwardly bowed circumferentially extending spring loops adapted to engage the inner surface of the bore.

ll. A lifting jacli comprising a standard having a cylindrical bore, a driving nutrotatably supported on the staiidard,an inteiioily and exteriorly threaded sleeve thread'- ed within the nut and adapted for longitudinal movement in the bore, a second lifting screw threaded within the sleeve, means for rotating the nut, and means for yieldably resist-ing rotary movement of the sleeve `within the bore comprising a wire spring,

the lower end portion of vthe sleeve being formed with a plurality ofvcircumferentially spaced substantially radial openings, the

spring being engaged in a pair of opposite openings, and each end portion being looped outwardly `and circumferentially of the sleeve withvthe free end inserted inwardly through another ofthe openings.

5. A lifting `jack comlirising a standard having a cylindrical bore, a driving nut rotatably supported on the standard, an interiorly and exteriorly threaded sleeve threaded within the nut and adapted for longitudinal movement in the bore, a second lifting screw threaded within the sleeve, means for Vrotating the nut, and meansfor yieldably' resisting rotary movement of the sleeve within the bore comprising a wire spring, the lower end portion of the sleeve being formed with a plurality of circumferentially spacedV radial openings, the springbeing positioned in the openings so as to form outwardly bowed circumferentially extending spring loops adapted to engage the inner surface of the bore. i y

6. A lifting jack comprising a. standard having a cylindrical bore, a driving nut rotatably supported on the standard, an in teriorly and exteriorly threaded sleeve 1' threaded within the nut and adapted for teriorly and longitudinal movement in the bore, la second lifting screw "threaded x within @the sleeve,

means for rotating thevnut,and means 'for yieldably 'resisting rotary," movement of the `sleeve within the bore comprising a wire spring, `the lower endV portion of the sleeve being formed with a plurality of circumferentially spaced substantially radial openings,

\ the spring being positioned in the openings so as to form an outwardly bowed circumferentially extending spring loop adapted to engage the inner surface ofthe bore.

7. A lifting jack comprising a standard having a cylindrical bore, a driving nut rotatably supported on the standard, an inexteriorly threaded sleeve threaded within the nutV and adapted for longitudinal movement in the bore, a second lifting screw threaded within the sleeve, means for rotating the nut, and means for y yieldably resisting rotary movement of the sleeve within the bore comprising `a wire spring consisting of a substantially straight central portion and a pair of spring loops bent in opposite directions in the same plane from the ends of the central portions, the free ends of the loops projecting inwardly toward one another,'the lower end of the sleeve being formed with a pair of substantially diametrically opposed open slots and a pair of substantially opposed radial openings, the

straight central portion of the spring being positioned in the slots and held in place by partially closing the open ends of the slots, and the free ends of the spring being movably engaged in the openings. Y

8f A lifting jack comprising a. standard having a cylindrical bore, a driving nut rotatably supported on the standard, an interiorly and exteriorly threaded sleeve threaded within the nut and adapted for longitudinal movement in the bore, a second lifting screw threaded within the sleeve, means for rotating the nut, and means for yieldably resisting rotary movement of the sleeve within the bore comprising a Wire spring consisting of a substantially straight central portion and a pair of spring loops bent in opposite directions in the same plane from the ends of the central portions, the free ends of the loops projecting inwardly toward one another, the lower end of the sleeve being formed with a plurality of substantially radial openings in which the spring is positioned, the straight central portion of the spring being locked in certain of the openings and the free end portions being slidably positioned in other openings.

9. A lifting jack comprising a standard having a cylindrical bore, a driving nut rotatably supported on the standard, an in- `teriorly and exteriorly threaded sleeve threaded within the nut and adapted for longitudinal movement inthe bore, a second lifting screw threadedy within the sleeve,

means. for rotating the nut, and means for yieldably resisting rota-ry movement of the sleeve within the bore comprising a- Wire spring consisting of a substantially straight central portion and spring loops extending from the respective ends thereof, the lower end of the sleeve being formed with e pair of l dametrically opposed radial openy slots in which the spring s-postioned and locked in place by peening inwardly the edge portions of the slots.

` GUNNAR JENSEN. 

